New construction along with pre-fabricated commercial buildings, residential buildings, and homes are typically designed with at least one rough opening for an enclosure such as a conventional hinged door. Conventional techniques would typically require a carpenter or skilled tradesman to install a custom header and casings sized to accommodate the selected door assembly for the specified opening. Typically one of two vertical jambs forming the sides of the rough opening would include hinges for attaching to the door for pivotal movement and the other of said jambs would include a strike plate for latching the door in a closed or locked position. The vertical jambs and a header horizontally connecting the vertical jambs are typically plumbed and squared during installation of the door assembly in the rough opening by placing wooden shims between the jambs and rough opening around its perimeter. Such conventional custom build approach is labor, cost, and time intensive.
To reduce the costs associated with the custom on-site door construction, door assemblies are now prefabricated to fit the rough opening in the home or building. However, in order to meet the desires of home or building owners' needs, the width of the rough openings would vary as a result of the differing thicknesses of the walls. Undesirably, a large inventory of prefabricated door assemblies would result in order to accommodate the unlimited number of wall thickness sizes. In addition to the surplus inventory problems relating to prefabricated doors, conventional custom build approach as well prefabricated doors typically leave screws and nails exposed from the outside of a door casing surrounding the door jambs and header.